1. Field of the Invention
The present invention relates to a printer selectively employing a continuous paper or a cut paper and being provided with a paper bail roller and, more particularly, to a printer which is capable of selectively performing a print operation on a continuous paper or a cut paper using a single driving source, and is provided with a paper bail moved between a position contacting a platen and a position separated from the platen by the single driving source.
2. Description of Related Art
A conventional printer is capable of selectively feeding a print medium such as a continuous paper or a cut paper because the drive force of a paper feed step motor is always connected to the cut paper feeder and is either connected to or disconnected from a pin feed tractor for feeding continuous paper to thereby enable paper selection. In this type of printer, the paper feed step motor is directly connected to a platen by a timing belt or the like and pressure rollers for feeding the cut paper are disposed under the platen. The cut paper is inserted between the platen and the pressure rollers to be fed together with the rotation of the platen. The platen is provided with a platen gear for transmitting the drive force to the pin feed tractor.
The platen gear is meshed through a clutch gear with a pin feed tractor driving gear. The clutch gear is mounted on a clutch lever supported on a side frame and is movable between positions so as to be engaged with the pin feed tractor driving gear or disengaged from the pin feed tractor driving gear according to movement of the lever. Namely, in the above-mentioned continuous paper/cut paper changeover operation, the pin feed tractor is rotated according to the rotation of the platen when the clutch gear is engaged to feed the continuous paper. On the other hand, when the clutch gear is engaged, the continuous paper feed operation is not performed and the cut paper is fed between the platen and the pressure rollers by a cut sheet feeder or by a hand so that the cut paper feed operation is performed by the rotation of the platen.
Meanwhile, the paper bail roller is closed so that the print medium is fed on the platen. The paper bail roller is opened for inserting the print medium between the paper bail roller and the platen. The paper bail roller is rotatively mounted on a shaft extending between paper bail levers supported on the right and left side frames. In setting the print medium in the printer, the paper bail levers are moved to position the paper bail roller in front of the upper portion of the platen in an open state. The print medium is inserted between the platen and the paper bail roller and then the paper bail levers are moved in the opposite direction to place them in a closed state.
In this state, the print medium is fed by the pressing force and rotation of the paper bail roller together with the rotation of the platen.
It is desirable that the continuous paper/cut paper changeover operation and the paper bail roller opening/closing operation described above should be performed the minimum amount of time at the optimum timing. It is necessary to individually use a step motor, a plunger solenoid or the like as drive sources.
Although it is generally desirable for it to be manufactured at a low cost, provision of multiple drive sources has become a problem by making the printer a high cost item.